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Babies exclusively breastfed are at less risk of obesity in their first year, study finds

A 24-hours-old baby after breastfeeding.AFP/Getty Images

Canadian researchers looked at data from thousands of breastfeeding mothers for a new study and found that infants who were exclusively breastfed were at less risk of obesity within the first year of their life.

The study, published in the October issue of the medical journal Pediatrics, also noted that the method of delivery was important, that is, feeding milk directly from the breast versus bottle-feeding infants breast milk was more beneficial.

“Feeding expressed breast milk from a bottle appeared to have a weaker beneficial effect on infant weight compared with direct feeding at the breast,” said Dr. Meghan Azad, a Canada research chair in developmental origins of chronic disease at the University of Manitoba, in a statement. “Although expressed milk was still beneficial compared to infant formula.”


The study, which tracked both the body mass index and the rate of weight gain in the infants, was conducted with data from the Canadian Healthy Infant Longitudinal Development (CHILD) study, where researchers are following certain families and tracking their children’s growth and development into adolescence.

Azad, who led the study, said in a statement that possible reasons as to why breast milk from a bottle wouldn’t be as beneficial was due to the process of storage.

Freezing, thawing, and heating breast milk could degrade components in it. Another thought was that babies fed directly from the breast would better self-regulate.

Using hospital records and information provided by families about their babies’ diet over the first two years, researchers also found the risk of obesity at 12 months was more than three times higher in infants who were not breastfed compared to infants who were exclusively breastfed.

Breastfeeding advocates say the study bolsters what they already knew about the long-term benefits of breastfeeding. More than 80 percent of mothers in Massachusetts choose to breastfeed, according to the Centers for Disease Control and Prevention.


“It becomes especially important if there’s a history of obesity in the family,” said Marsha Walker, a registered nurse, lactation consultant, and former board member with the Massachusetts Breastfeeding Coalition.

Cristela Guerra can be reached at Follow her on Twitter @CristelaGuerra.